Oh, I just thought of another thing that pisses me off: littering. For instance, at my school we have a fairly large room called the Student Center, although some refer to it as the "Fishbowl" (because the east and west side walls are almost complete glass). All of last week it was closed due to "Students littering." ...Honestly?
Unless your damn face is broken, there is no reason why you shouldn't be able to pick up an empty loving lunch tray and bring it the 4015 steps back to the cafeteria.